TheSamba.com :: View topic

Thu May 10, 2018 8:51 am

So back story is this is a industrial hair dryer for a dog grooming setup, and its just two hefty fans hooked to a 120v socket via a dual pole dual throw toggle switch. The wiring shorted out and burn the switch, along with the wire leads, so I couldn't just buy a switch and replace it. Had to cut new leads and the like. The dryer has two motors in it, and a "hi" and "low" setting with flipping the switch up or down. I figured one motor running would be low, and two motors running would be high (I may be completely wrong on this...maybe the fans are given different voltages somehow).

This is the drawing that I came up with to give one fan power with the switch down, and two fans power with the switch up. Does this make sense? I tried it last night and it didn't seem to work...but I feel like its wired correctly.

Thoughts?

Thu May 10, 2018 12:12 pm

It would have been wise to see how the old switch was wired prior to cutting the wires off, doing so would have given you a guide as to how to wire the new switch as well as tell you how the circuit was intended to function.

Hindsight is always 20/20. :wink:

Couple things you may want to consider:
- Is the new switch rated sufficiently for the load?
- Were the fans damaged when the wiring shorted, ie, do they even still work?
- What caused the previous wiring short and has it been corrected?
- Have you verified the remaining wires you are using are not also damaged?

Insomuch that you tried it last night and it didn't seem to work, please describe exactly what it is doing.

Thu May 10, 2018 12:25 pm

kangaboy wrote: The wiring shorted out and burn the switch, along with the wire leads, so I couldn't just buy a switch and replace it. Had to cut new leads and the like.

Yeah, I would have totally done that. One side was slightly intact, but I thought I would be able to figure it out. Guess not.
So I can confirm that both of the fans are working. Also, the wiring to the fans and from the socket are good. The only issue was a short at the switch. I don't know if a little water got in there gradually over time, or if the switch failed, or if something broke on the inside of the switch. The new switch I bought is rated for more load than the previous one, so we should be good there. I guess I'm just going to wire it up in a way that doesn't cause any shorts and see what I can make happen. The more I think about it, the more I think I wired it correctly and just had the intake port covered up so it made it seem like the fans were blowing backwards.

Thu May 10, 2018 12:44 pm

Here is my seconds attempt. Took out the neutral side of things and run them directly to the fan, and just toggle power.

Thu May 10, 2018 3:06 pm

My first thought was- there is a groomer around the corner? My second thought was-is there a seperate on/off switch with second attempt? Looks like you nailed hi@low?

Thu May 10, 2018 3:22 pm

kangaboy wrote: Here is my seconds attempt. Took out the neutral side of things and run them directly to the fan, and just toggle power.

That should work, but you're putting the full load of both fans through the 4/2 contacts which will cause them to burn out sooner. I think you'd be better off with power coming into 3 and 4, connect 1 to fan 1 power input, connect 2 to fan 2 power input, and jumper 2 to 6. That'll spread the electrical load evenly across the contacts.

Fri May 11, 2018 12:37 pm

cbeck wrote: My first thought was- there is a groomer around the corner?

Yep. High Ridge Animal Hospital does grooming and boarding. Bring the dogs/cats up for a spa day sometime! :D

Fri May 11, 2018 5:37 pm

Try not to overthink it.

You want one fan on low, two fans on high with a DPDT switch?

If the switch is an ON-OFF-ON switch, when the switch is in the middle position, now power flows and both fans are off.

Tie pins 3 and 4 together to 120V hot.
Tie pins 1 and 5 together to leg one of the low fan.
Tie pin 6 to leg one of the high fan.
Tie legs 2 of the low fan and high fan to 120V neutral.

When the switch is down:

pin 3 is connected to pin 1
pin 4 is connected to pin 2
power reaches the low fan

When the switch is up:

pin 3 is connected to pin 5
pin 4 is connected to pin 6
power reaches the low fan and the high fan

In this configuration, an equal amount of power flows through all contacts and the switch will wear normally.